Patent Literature 1 discloses a physiological condition estimation device that estimates the physiological condition of a target person, such as the driver of a vehicle. The physiological condition estimation device calculates an eye-blink rate and the interval between eye blinks to calculate a log-transformed value, calculates the frequency distribution of the interval between eye blinks at a predetermined time interval, and calculates the standard deviation of the log-transformed value and the average value of the frequency distribution. In addition, the physiological condition estimation device determines an arousal-level reduced condition from a value obtained by dividing the standard deviation by the average value and the cluster eye blink determined from the time interval between eye blinks. The physiological condition estimation device determines the arousal-level reduced condition. The arousal-level reduced condition means a condition in which, as the eye-blink rate and the cluster eye-blink rate increase, the entire eye blink distribution becomes irregular. In addition, a physiological condition estimation device has been proposed which estimates attentiveness to video content and estimates the physiological condition of the driver (for example, see Patent Literature 2). Furthermore, a physiological condition estimation device has been proposed which estimates the arousal level from the ratio of the eye-closed time and the degree of the opening of the eye of the driver (for example, see Patent Literature 3).